25C0007R0 4-20 MADC ISOLATED OUTPUT BOARD (REPLACES OEM 620433 & 621023)

Description: This is an isolated signal analog output card used industry wide. The analyzer’s potentiometric output (DC volts) signal drives the signal for the 4-20 mADC card (usually 0VDC input = 4 mADC output & 5 VDC input = 20 mADC output). The term “isolated” refers to the fact that the output signal is not referenced to earth ground and is therefore much less susceptible to interference from other voltage sources. Milliamp signals are very useful when running long signal loops (on the order of tens of feet to thousands of feet long; note that total loop resistance has to be less than 850 ohms).

Where used: 400A,755,755A,755R,870

Static sensitive: This board is not very susceptible to ESD but handle it with some ESD protocols.

Replaces: Rosemount 620433 (in kit p/n: 621023)

Compatibility: RIGAS has released its compatible version of the OEM board. Some nice enhancements were included: [1] hook-type test points, [2] better labeling, [3] heat sinks, [4] zero & span potentiometers can dual configuration (i.e., adjustable from the top or from the front).

Please specify potentiometer type when ordering. Choices: [1] end adjust or [2] top adjust

Typical failure modes (after many years of service): [1] total failure: most likely due to the fullwave bridge rectifier or output opamp. [2] non-linearity: most likely due to the charge pump circuit. [3] inability to calibrate: most likely due to the charge pump circuit. [4] noisy output: output opamp is failing –or– input signal is noisy –or– board mounted isolated power supply(ies) are failing –or– loop resistance is very high –or– it could be that your mADC reader (DCS, DAS, etc) is misbehaving.

Repairable: Yes!  Call us at 877-616-0600 for an RMA number.

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