iC-RC1000
SIN/COS SIGNAL SAFETY MONITOR IC
Rev B1, Page 2/10
DESCRIPTION
iC-RC1000 acts as an independent monitoring de- So that the external controller can safely detect an
vice for industrial safety controllers and drive systems interrupt, the status times are extended to at least
in the evaluation of sine encoders for SIL applica- 10 ms by retriggerable monoflops. After power on iC-
tions.
RC1000 starts in Signal error status, setting the Sig-
nal OK status at the earliest after the monoflop pe-
In this function the IC checks that four analog signal riod has elapsed. The status outputs are configured
lines have the correct DC voltage range (DC range: as push-pull drivers so that optocouplers can be di-
30 to 80 % from VCC1 or VCC2) and that two respec- rectly connected up to the device (10 mA low side,
tive paired lines have the correct differential 1 Vpp 4 mA high side).
signal amplitude in real time (amplitude range: 200
to 300 mV). Signals with twice this amplitude (400 to The front end signal splitter isolates the two diagnos-
600 mV) referenced to ground can also be monitored; tic channels from one another and provides protec-
here, the negative input must be kept within the per- tion against overvoltage with the help of external re-
missible DC range (e.g. VCC/2).
sistors (39 kΩ at each signal input). The integrated
clamp circuit then reduces the input voltage to within
iC-RC1000 has intrinsic safety, enabling single er- the permissible range. At the same time this de-
rors to be securely identified through redundancy; in- couples the signal source so that a controller can
dependently of one another, two different diagnostic simulate an error by loading an input pin. So that
channels monitor the input signals, outputting sepa- signal failures can be detected should there be a
rate messages. The Signal OK and the Signal er- fractured cable, for example, integrated pull-down re-
ror statuses are complementary to one another if the sistors (2.5 MΩ) drag the DC potential into the error
chip is functioning correctly.
range.
Each diagnostic channel has signal comparators iC-RC1000 works with a supply voltage of 5 V. The
for DC and square sum monitoring; the monitoring diagnostic channels can be supplied by one or two
windows have a different design depending on the separate power packs and mutually monitor the ap-
good/bad diagnosis. The square sum monitor uses plied supply voltage. The device is protected against
an analog multiplier and calculates the Lissajous ESD and in the given circuit is overvoltage-proof at
curve derived from the square signal by the sine and the front end up to 36 V.
cosine (sin(wt)2 + cos(wt)2).
ICHAUS [ IC-HAUS GMBH ]
