103 Volts, dc, 2mV range 104 Volts, dc, 10mV range 310-314 Thermocouple type E The third digit sets the range: 0 = auto-ranging, 4 = least sensitive range (10V) *Type B and N thermocouples may be used only with an IMP marked with product status C3 onwards 320-324 Thermocouple type J 330-334 Thermocouple type K 340-344 Thermocouple type R 350-354 Thermocouple type S 360-364 Thermocouple type T 370-374 Thermocouple type B* 380-384 Thermocouple type N* 500 Current, dc, auto-ranging Channels used for current measurements require the fitting of a 100Ω shunt. (See IMP Installation Guide) 501 Current, dc, 200µA 502 Current, dc, 2mA 503 Current, dc, 20mA 504 Current, dc, 100mA Table 2.4: Mode codes for IMP type 1B (Strain) Code, m Mode Set Comments 000 Skip There is no ‘10V range’ 100 Volts, dc, auto-ranging 101 Volts, dc, 20mV range 102 Volts, dc, 200mV range 103 Volts dc, 2V range Resistance, 4-terminal 200 0.8mA drive, auto-ranging 201 0.8mA drive, 25Ω range 202 0.8mA drive, 250Ω range 203 0.8mA drive, 2k5Ω range Resistance, 3-terminal *Only an IMP with a product status of C6 (or higher) are able to comply with an auto-ranging command 210 0.8mA drive, auto-ranging 211 0.8mA drive, 25Ω range 212 0.8mA drive, 250Ω range 213 0.8mA drive, 2k5Ω range RTD/PRT, 100Ω, 4-terminal 400 “auto-ranging 411 “20mV range 412 “200mV range 413 “2V range RTD/PRT, 100Ω, 3-terminal 410 “auto-ranging * Only an IMP with a product status of C6 (or higher) are able to comply with an auto-ranging command 411 “20mV range 412 “200mV range 413 “2V range
Strain Gauges: 600-603 ½ - bridge 4mA dual current The last digit in the code sets the range: 0 = auto-ranging, 1 = 200mV range, 2 = 200mV range, 3 = 2V range 610-613 ½ - bridge, 0.8mA dual current 620-623 ¼ - bridge, 4mA dual current 630-633 ¼ - bridge, 0.8mA dual current 640-643 Full-bridge, 8mA drive 650-653 Full-bridge, 1.6mA drive 660-663 Three-wire, 4mA drive 670-673 Three-wire, 0.8mA drive Table 2.5: Mode Codes for IMP type 2A (Digital) Code, m Mode Set Comments 000 Skip 700 Digital status Event count totalise: On receipt of a measurement trigger, keeps a continuous count of events. This count may be cleared either by the CL command or by setting the channel mode again to event count totalise. 740 -ve going edge. 741 +ve going edge. 742 +ve or –ve going edge Event count increment: A continuous count of events is kept since the last trigger. On receipt of the next trigger, the event count is stopped, the result is sent to the PC and another event count is begun. 750 -ve going edge 751 +ve going edge 752 +ve or –ve going edge Event capture: 760 -ve going edge Enabled by EV command only 761 +ve going edge 762 +ve or –ve going edge 800 Switch output off (high) For digital output, set channel to logic ‘1’ or ‘0’ 801 Switch output on (low) Frequency Measurement: 900 gate time = 10ms 901 gate time = 100ms 902 gate time = 1s 903 gate time = 10s Multiple periods: Returns the time over which periods are counted. Measurement starts on the negative-going edge. 910 1 period 911 10 periods 912 100 periods 913 10000 periods ‘One-shot’ time: 920 -ve going start, +ve going stop Measures –ve pulse width
921 +ve going start, -ve going stop Measures +ve pulse width Note: -ve edge refers to a negative-going edge, a transition from high to low. +ve edge refers to a positive-going edge, a transition from low to high. Event Count This facility permits a number of events to be counted. The events (transitions) to be included in the count can be +ve, -ve or both. Two types of count are offered: increment or totalise. These operate as follows: Increment. On receipt of a measurement trigger, an event count is started. Then on receipt of another measurement trigger, the event count is stopped. The result is sent to the 3595 4C Interface card and another count begins. Totalise. On receipt of a measurement trigger, events are counted until an HA (halt) command is received or until the channel mode is set to Event Count Increment. In the latter case, the counter is cleared prior to starting the incremental count. If a CL (clear) command is received at any time, the event counter is reset to zero. A new count is started on receipt of the next measurement trigger. The event counter of a particular channel is also cleared when that channel is set again to the totalise mode. The maximum number of events that can be recorded per channel by the circuitry is 16,777,215, after which the rolls over to zero. No indication of this is given. Table 2.6: Mode Codes for IMP type 2A (Switch IMP) Code, m Mode Set Comments 000 Skip 700 Digital Status Event capture: Enabled by EV command only. 760 -ve going edge 761 +ve going edge 762 +ve or –ve going edge 800 Switch output off (high) For digital output, sets channel to logic ‘1’ or ‘0’ 801 Switch output on (low) Note: -ve edge refers to a negative-going edge, a transition from high to low. +ve edge refers to a positive-going edge, a transition from low to high. Channels 29 to 32 are digital input/output channels. Digital outputs are set when the IMP devices receive the relevant CH MO command. For more details on each individual mode, refer to the IMP Installation Guide. Table 2.7: Mode Codes for IMP type 1H and 1J counting
Table 2.16: Default sample rates Mode Default Sample Rate Digital status 20Hz Event counting 1Hz Event capture 1kHz Frequency 100kHz Period 100kHz One-shot time 100kHz CH TI (set CHannel TIme-out) Where: n is an integer that defines the channel number, in the range 1 ≤ n ≤ 20 p is an integer that defines the time-out code, in the range 0 ≤ p ≤ 5 Note: This command applies only to IMP types 1H, 1J and 2A. Function: For a specific channel, sets the time-out period for period measurements. The settings available are listed in Table 2.17. The default period is 2 seconds (p = 1) The time-out period is the maximum time any period or ‘one-shot’ measurement is allowed to take. If the period to be measured exceeds this time, the error ‘period is returned instead of a result. For single period measurement of cyclic signals, the time-out period must be at least twice that of the measured signal. This ensures both edges of the signal are within the time-out period. Response: None Table 2.17: Time-out periods Time-out code Time-out Period 0 200ms 1 2s 2 20s 3 50s 4 70s* 5 130s* * Available on 1H and 1J IMP types only CL (CLear event totalise counter)