Connect the wires for the 16 RTDs directly to the two terminal blocks on the terminal board. Each block is held down with two screws and has 24 terminals accepting up to #12 AWG wires. A shield terminal strip attached to chassis ground is located immediately to the left of each terminal block.
In a TMR Mark VI control system, TRTDH1B provides redundant RTD inputs by fanning the inputs to three VRTD boards in the R, S, and T racks. The inputs meet the same environmental, resolution, suppression, and function requirements and codes as the TRTDH1C terminal board; however, the fast scan is not available.
How to operate：
TRTD supplies a 10 mA dc multiplexed (not continuous) excitation current to each RTD,which can be grounded or ungrounded. The 16 RTDs can be located up to 300 m (984 ft) from the turbine control cabinet with a maximum two-way cable resistance of 15 Ω.
The A/D converter in the VRTD samples each signal and the excitation current four times per second for normal mode scanning and 25 times per second for fast mode scanning, using a time sample interval related to the power system frequency. Software performs the linearization for the selection of 15 RTD types.
RTD open and short circuits are detected by out-of-range values. An RTD that is determined to be outside the hardware limits is removed from the scanned inputs to prevent adverse effects on other input channels. Repaired channels are reinstated automatically in 20 seconds or can be manually reinstated.
All RTD signals have high-frequency decoupling to ground at signal entry. RTD multiplexing in the VRTD is coordinated by redundant pacemakers so that the loss of a single cable or VRTD does not cause the loss of any RTD signals in the control database.The VRTD is a remote RTD I/O processor board.
How to diagnose：
Diagnostic checks include the following:
• Each RTD type has hardware limit checking based on preset (non-configurable) high and low levels set near the ends of the operating range. If this limit is exceeded,a logic signal is set and the input is no longer scanned. If any one of the input’s hardware limits is set, it creates a composite diagnostic alarm, L3DIAG_xxxx,referring to the entire board. Details of the individual diagnostics are available from the toolbox. The diagnostic signals can be individually latched, and then reset withthe RESET_DIA signal.
• Each RTD input has system limit checking based on configurable high and low levels.These limits can be used to generate alarms, and can be configured for enable/disable,and as latching/non-latching. RESET_SYS resets the out of limit signals. In TMR systems, limit logic signals are voted and the resulting composite diagnostic is present in each controller.
• The resistance of each RTD is checked and compared with the correct value, and if high or low, a fault is created.
• Each connector has its own ID device, which is interrogated by the I/O processor board. The terminal board ID is coded into a read-only chip containing the terminal board serial number, board type, revision number, and the connector location. If a mismatch is encountered, a hardware incompatibility fault is created.
Product Application
Our products are widely used in CNC machinery and metallurgy, oil and gas, petrochemical, chemical, paper printing, textile printing and dyeing, machinery, electronics manufacturing, automobile manufacturing, tobacco, plastic machinery, electricity, water conservancy, water treatment / environmental protection, municipal engineering, Heating, energy, transmission and distribution industries.
Product Application
Our products are widely used in CNC machinery and metallurgy, oil and gas, petrochemical, chemical, paper printing, textile printing and dyeing, machinery, electronics manufacturing, automobile manufacturing, tobacco, plastic machinery, electricity, water conservancy, water treatment / environmental protection, municipal engineering, Heating, energy, transmission and distribution industries.
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