MAX15500_11 Datasheet, PDF (17/28 Pages) Maxim Integrated Products – Industrial Analog Current/ Voltage-Output Conditioners

Industrial Analog Current/
Voltage-Output Conditioners
Output Monitor
The MON output provides an analog voltage signal
proportional to the output voltage in current mode and
proportional to the output current in voltage mode. Use
this signal to measure the system load presented to the
output. The full-scale signal on MON is 3V with a typical
accuracy of 10%. The signal range is typically 1.5V to 3V
in unipolar mode and 0 to 3V in bipolar mode.
In current mode, the MAX15500/MAX15501 program IOUT
and monitor the voltage at SENSERN.
VMON = 1.425V + (VSENSERN/20)
RLOAD = ((VMON - 1.425V) x 20)/IOUT(PROGRAMMED)
In voltage mode, the MAX15500/MAX15501 program
VOUT and monitor IOUT.
VMON = 1.521V + 62.4 x ILOAD
RLOAD = VOUT(PROGRAMMED)/((VMON - 1.521V)/62.4)
Error Handling
Many industrial control systems require error detection
and handling. The MAX15500/MAX15501 provide exten-
sive error status reporting.
An open-drain interrupt flag output, ERROR, pulls low
when an error condition is detected. An error register
stores the error source. Reading the error register once
resets the ERROR pin but not the error register itself,
allowing the system to determine the source of the error
and take steps to fix the error condition. After the error
condition has been fixed, read the error register for the
second time to allow the device to clear the error reg-
ister. Read the error register for the third time to verify
if the error register has been cleared. If another error
occurs after the first read, ERROR goes low again. More
information on reading and clearing the error register is
described in the SPI Interface section.
When an output short-circuit or output open-load error
occurs and disappears before the error register is read,
the intermittent bit is set in the error register. The intermit-
tent bit does not assert for brownout and overtempera-
ture error conditions.
Error Conditions
Output Short Circuit
The output short-circuit error bit asserts when the output
current exceeds 30mA (typ) for longer than 260ms. In
current mode, this error occurs when the sense resistor
is shorted and the sense voltage is not equal to 0V. In
voltage mode, this error occurs when the load is shorted
to the supply or ground. The short-circuit error activates
the intermittent bit in the error register if the error goes
away before the error register is read.
VOUT OR IOUT
FS + 20%
FS + 5%
FS
FSMODE = DGND
5%FS
FSMODE = DVDD
VAIN
FS
Figure 1. Unipolar Transfer Function
VOUT OR IOUT
FS + 20%
FS + 5%
FS
FSMODE = DGND
50%FS
-FS
-FS - 5%
-FS - 20%
FSMODE = DVDD
Figure 2. Bipolar Transfer Function
VAIN
FS
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