Configuration Variable/Proposed CV Changes

This is a list of proposed changes to the Configuration Variables. This is copied from a draft published in 2023.
Items marked in RED are proposed changes.
S-9.2.2 DRAFT
Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023	Multi-function Decoder Configuration Variables Draft Version S-9.2.2 Jan 2023
CV Name 	CV # 	Required[2] 	Default Value 	ReadOnly 	UniformSpec 	Dynamic(Volatile) 	Comments
Primary Address 	1 	M 	[3] 	 	Y 	 	Do Not Set to Zero! [4]
VStart 	2 	M 	 	 	 	 	
Acceleration Rate 	3 	M 	 	 	 	 	
Deceleration Rate 	4 	M 	 	 	 	 	
VHigh 	5 	M 	 	 	 	 	
VMid 	6 	M 	 	 	 	 	
Manufacturer Version 	7 	M 	 	Y 	 	 	Manufacturer defined version info
Manufacturer ID 	8 	M 	 	Y 	Y 	 	Values assigned by NMRA [5]
Total PWMPeriod 	9 	O 	 	 	 	 	Nominal PWM period at the decoder's motor output [6][7]
BEMFFeedback Cutout 	10 	O 	 	 	 	 	Contains a value between 1 and 128 that indicates the speed step above which the Back EMF motor control cuts off. When 14 or 28 speed steps are used the LSB's of the value are truncated appropriately.
Packet Time-Out Value 	11 	R 	 	 	 	 	Set time to stop vehicle if DCC signal lost. [8]
Power Source Conversion 	12 	O 	 	 	Y 	 	Values assigned by NMRA. See note regarding CV1.
Alternate Mode Function Status F1 – F8 	13 	O 	 	 	Y 	 	Indicates the status of each function (F1 – F8) when the unit is operating in alternate power mode, which cannot control the functions. If a function can be controlled, then the corresponding bit is ignored. A value of "0" indicates the function is off, while a value of "1" indicates the function is on. Bit 0 corresponds to F1, Bit 7 to F8.
Alternate Mode Function 2 Status FL, F9-F12 	14 	O 	 	 	Y 	 	Indicates the status of each function (F9 to F12, plus FL) when the unit is operating in alternate power mode, which cannot control the functions. If a function can be controlled, then the corresponding bit is ignored. A value of "0" indicates the function is off, a value of "1" indicates the function is on. FL in the forward direction is controlled by bit 0, FL in the reverse direction is controlled by bit 1. Bit 2 corresponds to F9, Bit 5 to F12.
Decoder Lock 	15 – 16 	O 	0 	 	Y 	 	Used to control decoder programming when more than one decoder is present at that address. If CV15 does not match CV16 any programming instructions are ignored.
Extended Address 	17+18 	O 	M 	 	Y 	 	These two bytes form the Extended Address. [9]
Consist Address 	19 	O 	R 	 	Y 	 	Contains the seven bit Consist Address in bits 0 − 6. [10]
EXTENDED CONSIST ADDRESS 	20 	 	 	 	Y 	 	Reserved by NMRA for future use: Experimental use of extended address consists initially proposed by Zimo
Consist Address Active for F1 – F8 	21 	O 	 	 	Y 	 	Defines for functions F1 – F8 whether the function is controlled by the consist address. For each Bit a value of "1" indicates that the function will respond to instructions addressed to the consist address. A value of "0" indicates that the function will only respond to instructions addressed to the locomotive address. F1 is indicated by bit 0. F8 by bit 7.
Consist Address Active for FL – F9 – F12 	22 	O 	 	 	Y 	 	Defines for function FL whether the function is controlled by the consist address. For each Bit a value of "1" indicates that the function will respond to instructions addressed to the consist address. A value of "0" indicates that the function will only respond to instructions addressed to the locomotive address. FL in the forward direction is indicated by bit 0, FL in the reverse direction is controlled by bit 1. Bit 2 corresponds to F9, while Bit 5 controls F12.
Acceleration Adjustment 	23 	O 	 	 	Y 	 	This Configuration Variable contains additional acceleration rate information that is to be added to or subtracted from the base value contained in CV3. This is a 7 bit value (bits 0 – 6) with bit 7 being reserved for a sign bit (0 – add, 1 – subtract). In case of overflow the maximum acceleration rate shall be used. In case of underflow no acceleration shall be used. The expected use is for changing momentum to simulate differing train lengths/loads, most often when operating in a consist.
Deceleration Adjustment 	24 	O 	 	 	 	 	This Configuration Variable contains additional braking rate information that is to be added to or subtracted from the base value contained in CV4. See CV23 for additional details.
Speed Table/Mid-range Cab Speed Step 	25 	O 	 	 	Y 	 	A value between 2 and 127 shall be used to indicate 1 of 126 factory preset speed tables. A value of 0000 0010 indicates a linear curve shall be used. A value between 128 and 154 defines the 28-speed step position (1 − 26) which will define where the mid-range decoder speed value will be applied. In 14-speed mode the decoder will utilize this value divided by two. If the value in this variable is outside the range, the default mid cab speed of 14 (for 28 speed mode or 7 for 14 speed mode) shall be used as the mid speed value. Values of 0000 0000 or 0000 0001 shall indicate that this CV is not used.
 	26 	O 	 	 	 	 	Reserved by NMRA for future use
Decoder Automatic Stopping Configuration 	27 	O 	 	 	Y 	 	Used to configure which actions will cause the decoder to automatically stop.
Bi-Directional Communication Configuration 	28 	O 	 	 	Y 	 	Used to configure decoder’s Bi-Directional communication characteristics when CV29 – Bit 3 is set.
Mode Control 	29 	M 	6 	 	Y 	 	[11]
Error Information 	30 	O 	 	 	Y 	 	In the case where the decoder has an error condition this CV shall contain the error condition as specified by the manufacturer. A value of 0 indicates that no error has occurred.
Index High Byte 	31 	O 	 	 	Y 	 	Primary index for CV257-512 [6] [12]
Index Low Byte 	32 	O 	 	 	Y 	 	Secondary index for CV257 – 512
Output Loc. FL(f), FL(r), F1 – F12 	33 – 46 	 	 	 	 	 	[13]
Manufacturer Unique 	47 – 64 	O 	 	 	 	 	Reserved for Manufacturer use
Kick Start 	65 	O 	 	 	 	 	Specifies the amount of extra Kick that will supplied to the motor when transitioning between stop and the first speed step.
Forward Trim 	66 	O 	 	 	 	 	Specifies a scale factor by which a voltage drive level should be multiplied, when the controller is driving the unit in the forward direction. [14]
Speed Table 	67 – 94 	O 	 	 	 	 	The speed table is defined to be 28 bytes wide, consisting of 28 values for forward speeds. A digital controller that uses this table shall have at least 64 voltage drive levels and can have as many as 256 so that a smooth power curve can be constructed.
Reverse Trim 	95 	O 	 	 	 	 	Specifies a scale factor by which a voltage drive level should be multiplied, when the controller is driving the unit in reverse. [15]
 	96 	 	 	 	 	 	Reserved by NMRA for future use [16]
 	97 – 104 	 	 	 	 	 	Reserved for manufacturer use
User Identifier #1 [17] 	105 	O 	 	 	 	 	Reserved for Customer Use
User Identifier #2 	106 	O 	 	 	 	 	Reserved for Customer Use
 	107 – 111 	 	 	 	 	 	Reserved by NMRA for future use. Expanded Mfg. ID, with CV8=0xEE a 16-bit manufacturer ID is stored in CVs 107,108. CVs 109-111: with CV7=_____, these three CVs expand the version number feature.
Manufacturer Unique 	112 – 256 	 	 	 	 	 	CVs in this range are already being used by many manufacturers. Opening up this area officially is an attempt to legitimize what is already being done.
Indexed area 	257 – 512 	 	 	 	 	 	Indexed area - see CV# 31,32, [18]
 	513 – 879 	 	 	 	 	 	Reserved by NMRA for future use
 	880 – 895 	 	 	 	Y 	 	Reserved by NMRA for future use. CVs in this range are dynamic and are used for Unsolicited Decoder Initiated Transmission.
Decoder Load 	892 	O 	 	 	Y 	Y 	Specifies the current load of the decoder. The load is volatile and is not stored across power interruptions. Bits 0-6 indicate the value of the load, 0 indicates no load. Bit 7 indicates a positive or negative load.
Dynamic Flags 	893 	O 	 	 	Y 	Y 	Up to 8 dynamic flags can be transmitted. Bits 0-7 are Reserved for Future Use.
Fuel/Coal 	894 	O 	 	 	Y 	Y 	Amount of Fuel/Coal remaining before the decoder will stop the locomotive. A value of 0 indicates that the Fuel/Coal is totally consumed, 254 indicates totally full. A value of 255 indicates that this CV is not currently supported and its contents should not be transmitted.
Water 	895 	O 	 	 	Y 	Y 	Water left before the decoder will stop the locomotive. A value of 0 indicates that all the water has been consumed, 254 indicates full. A value equalling 255 indicates that this CV is not currently supported and its contents should not be transmitted.
SUSI Sound and Function Modules 	897 – 1024 	O 	 	 	Y 	 	For use by SUSI to define CVs for Sound and Function auxiliary modules. [19] See TN-9.2.3