GENERAL DESCRIPTION The Thermocouple Input modules provide eight, eiectrically-isolated inputs for the detection of low-level, analog signals developed by thermocouple devices. These modules are available in seven versions: Type J, Type K+, Type S, Type T, Type B, Type E, and Type R. The features and benefits of the Thermocouple Input modules are summarized in Table 1. The modules contain two, four-channel, thermocouple conditioners; either four-channel conditioner can be reassigned for use with any of the seven thermocouple types (J, K+, S, T, B, E, or R). The low-level input signal conditioning includes f 1OOOV DC, isolation, high common mode rejection, filtering and low drift amplification. Signal integrity is further preserved by a highaccuracy programmable-gain amplifier and a 13-bit integrating A/D converter. The output of this converter constitutes a 13-bit word (12 bits plus sign) equivalent to k 4096 counts of resolution. renheit. The temperature value is sent, along with binary information giving various status conditions and the channel number, to the Input Status Table in the Series Six CPU. Temperature values transferred to the Series Six CPU can be in either sign magnitude or 2 s complement format, as jumper-selected by the user. The input channels are sampled at a rate of 15 or 30 readings per second (for 60 Hz settings). The factory-set sample rate of 15 samples per second gives a Normal Mode Rejection (NMR) of 86 dB for each input. (NMR indicates immunity to power-line frequency noise added to the low-level input signals.) Where NMR is of lesser importance, the sample rate can be doubled, to 30 samples per second. An external Cold-Junction Compensation element, which connects directly to the terminals on the module faceplate, eliminates the need for an ice-point reference function. An on-board microprocessor then scales, linearizes and Refer to Figure 1 (next page) for Thermocouple Input converts the input data to either degrees centigrade or fah- module specifications. TABLE 1. FEATURES AND BENEFlTS FEATURES BENEFITS Seven types available: Useful in variety of applications Type J Thermocouple Type B Thermocouple Type K Thermocouple Type E Thermocouple Type S Thermocouple Type R Thermocouple Type T Thermocouple Eight isolated inputs per module Low cost per input point Contains cold-junction compensation and linearization Direct interface to thermocouple devices routines Thirteen-bit resolution High conversion accuracy (1 part in 8192) Temperature readings in degrees C or F Ease of operation Open thermocouple detection Simplifies troubleshooting APPLICATIONS *NOTE: Total accuracy should also include accuracy of thermocouple wire. typically, f 1 or 2 C or 0.75%, whichever is greater. Module Drift* NOTE: These specifications describe worst case variations in accuracy of Thermocouple Input module temperature readings (established at time and temperature of calibration) resulting from changes in ambient temperature per degrees centigrade and progression of time in months. FIGURE 1. SPECIFICATIONS 2 Thermocouple Input Modules GEK-84867 FIGURE 2. USER ITEMS (Part 1 of 2) Ref. 70.TMP.10 3 Thermocouple Input Modules GEK-84867 0 Faceplate 0 Board OK LED: 0 User Connector Block OFF: If module has failed board diagnostics O Cold Junction Compensation Element ON: No module-level errors detected by board diagnostics Offset ADJ Pots 1-8: Adjust voltage offsets for circuits 1-8, respectively. (Refer to Calibration section.) O GAIN ADJ Pots 1-8: Adjust voltage gains for inputs 1-8, respectively. (Refer to Calibration section.) O Configuration DIP switch: (Refer to the following chart). DIP SWITCH ( q Contains Rocker Switch Number) RUN 1 - 2 Calibrate 2 - 3 0 Sample Rate Jumpers: The factory-set sample rate provides Normal Mode Rejection (NMR) of 86dB at either 50 or 60 Hz line frequencies where NMR is of lesser importance, the sample rate can be increased.