Fisher 244ER, 244EH manual FAILURE MODE Changing Switch Positions

Rosemount Models 244EH and 244ER PC-Programmable Temperature Transmitters

Figure 2-13. Transmitter Power, Sensor, and Configuration Terminals

FAILURE MODE

Changing Switch Positions

		Model 244EH		Model 244ER
			Sensor	Sensor Terminal
			Terminals
1	2	3	4		1105E01B
			Configuration
			Terminals	Failure Mode Switch
			Failure Mode	Power/Configuration	-1260B02D,
			Switch
				Terminals
			Power Terminal
					244

The Models 244EH and 244ER features software driven alarm diagnostics and an independent circuit. These features are designed to provide separate backup alarm output in case the microprocessor, electronics, hardware, or software fails. The alarm levels are user selectable using the Failure Mode Switch. The position of the jumper determines the direction in which the output is driven (HI or LO) in case of alarm. The jumper switch feeds into the Digital-to-Analog (D/A) converter, which drives the proper alarm output even if the microprocessor fails.

The values to which the transmitter drives its output in failure mode depend on whether it is factory configured to standard or NAMUR-compliantoperation. See “Failure Mode” on page A-2for these parameters.

To determine the failure mode configuration of a transmitter, review the low and high alarm levels on the SERVICE menu provided by the configuration software.

To change the failure mode on the Model 244EH or 244ER transmitter, follow the steps described below.

1. If the transmitter is mounted in an enclosure, remove the enclosure cover.

2.Locate the orange failure mode switch. The switch is located near the power terminals on the Model 244EH and in the center of the front panel on the Model 244ER (see Figure 2-13).

3.Move the switch to the desired alarm setting. To set the failure mode to high alarm, position the switch toward the “HI” mark on the terminal block; to set the failure mode to low alarm, position the switch in the opposite direction.

4. Replace the enclosure cover (if applicable). Enclosure covers must be fully engaged to meet explosion-proof requirements.

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